Drive unit for domestic ironing machines and the like



Oct. 6, 1953 J. F. YOUNG I 2,654,222

DRIVE UNIT FOR DOMESTIC IRONI NG MACHINES AND THE LIKE Original Filed Dec. 22, 1949 I 2 Sheets-Sheet l Fig.1.

James F. Young His Attorney.

J. F. YOUNG Oct. 6, 1953 DRIVE UNIT FOR DOMESTIC momma MACHINES AND THE LIKE Original Filed Dec. 22 1949 2 Sheets-Sheet 2 Fig.3.

'HIIIIH Inventor: James P. Young,

His Attorney.

Patented Oct. 6, 1953 DRIVE UNIT FOR DOMESTIC IRONING MACHINES AND THE LIKE James F. Young, Erie, Pa., assignor to General Electric Company, a corporation of New York Original application December 22, 1949, Serial No. 134,473. Divided and this application June 16, 1951, Serial No. 232,032

4 Claims.

This application is a division of my pending application, Serial No. 134,473, filed December 22, 1949, for Operating Mechanism for Domestic Ironing Machines and the Like.

The invention relates to domestic ironing machines of the flat plate ty e and, in particular, to an improved actuator for the pressing elements thereof.

Domestic flat plate ironing machines generally include a padded ironing table or buck on which the articles to be ironed are laid by the operator, and a heated shoe which is carried on an arm structure pivoted relative to the buck so that it can be brought into pressing position with relation thereto. By suitable mechanism, the respective elements are then brought together to press the articles therebetween. An ironing machine of this type is shown in Wardwell Patent 2,135,266, granted November 1, 1938, entitled Ironing Press, and owned by the General Electric Company, assignee of the present application. In the Wardwell ironer, the shoe is moved manually and, as it approaches the ironing position, switch means are automatically closed to energize a hydraulic motor system which drives the buck upwardly against the shoe.

The object of my invention is the provision of improved means for automatically bringing together the buck and shoe to carry out the ironing operation.

Another object of my invention is the provision of pressure-operated valve means in the hydraulic motor system to govern the rate of rise and return of the pressing elements.

A further object of my invention is to provide adjustable by-pass means in the hydraulic system to obtain substantially uniform operation of the hydraulic actuator despite, for example, variations of viscosity of the liquid content of the system and subnorm-al line voltage at the operating motor.

In a presently preferred embodiment of my invention, I carry out these and other objects by providing, in my hydraulic motor unit, pressure-operated valve members which establish one rate of fluid flow for pressure application against the piston of the motor as the shoe is rising, and a more rapid flow rate for the return flow of fluid so as to speed the return of the motor piston, and, consequently, the return of the shoe and buck after the ironing operation. This rapid return is accomplished smoothly because of the dashpot action of the piston and cylinder. In addition, I provide a novel by-pass arrangement which can be adjusted to control the pressure available on the underside of the piston, and thereby determine the rate of piston rise during the operation of the ironer.

In the accompanying drawing, Fig. 1 is a side elevation of an ironing machine showing the shoe and buck in retracted position; Fig. 2 is a top plan view of a piston head plate used in the hydraulic actuator, showing the pump cavity and valve outlet passages; and Fig. 3 is a sectional side elevation of the hydraulic motor unit embodying the present invention, the section being taken along lines 3-3 of Fig. 2.

Referring now to Fig. 1, the domestic ironing machine shown includes a frame structure I which is arranged in the form of a table having a rigid top 2 on which is mounted a cylinder 3, within which operates a hydraulic motor unit. As explained in detail hereinafter, said unit carres a buck 4 and is arranged to drive said buck upwardly to exert ironing pressure against a heated shoe 5, previously brought into operating position. The shoe 5 is carried by a rigid, substantially U-shaped, carriage 6, pivotally supported on a pair of pintles I which may be carried by hangers (not shown) extending from the cylinder 3. The cylinder is provided with a flange structure 8 disposed at an angle relative to the cylinder axis so as to support the cylinder in an angular relation with respect to the table top, as viewed in side elevation. The lower portion of the cylinder projects through an opening provided in the table top.

The shoe carriage 6 may be cushioned at the extremities of its travel toward or away from the buck by suitable means, such as the two pairs of springs 9 and I0 carried on rods ll pivotally aliixed beneath the table top 2 at opposite sides of the cylinder 3. Suitable adjustment nuts I2 and [3 are provided to regulate the tension of the springs, which bear against a pair of brackets l4 slidably mounted on the respective rods H. Each bracket is pivotally attached to an arm l5 afiixed to the carriage 6. It will be apparent that as the shoe arm rotates clockwise of Fig. 1, the spring 9 is compressed and that said spring may assist the returnof the carriage. The spring I0 cushions the carriage at the end of its return movement. It should be understood that the buck and the shoe are elongate and of substantial area, and that each is symmetrical with respect to the cylinder 3. It should be further understood that the pairs of rods l l and their associated springs and arms are preferably identical in size and shape.

Referring now to Fig. 3, I mechanically drive roller 38 until the over-center gravity position of the shoe and carriage is reached, following which such engagement is inherently maintained. The dashpot effect of the oil ports 46 and of the piston and cylinder is thus available to smooth the return movement of the shoe as well as of the buck. The buck rises slowly during its initial movement, and is accelerated during its upward travel as the load imposed on the motor unit by the shoe and carriage is lessened, in the manner previously explained.

Adjustable speed control of the piston and other operating advantages may be accomplished by the inclusion of a pressure by-pass system with cylinder 3, arranging the system so that its down stream end enters the cylinder at a point coinciding with the position of the piston when the shoe has reached its operating position, so that upon further motion of the piston equal pressure will be applied to both sides of the by-pass valve element to neutralize its effect. When'this occurs, maximum fluid pressure will then be available for the actual ironing operation and will depend upon the capacity of the fluid pump, without regard to the setting of the by-pass valve.

Referring again to Fig. 3, a suitable relief valve organization is shown, including a valve body 49 shaped to the curvature of the cylinder and welded or otherwise secured thereto in leakproof relationship. The valve body is bored to provide a flow circuit comprising the interconnected upstream and downstream legs 50 and which communicate with the cylinder, as shown. A sleeve 52 is fixed to the valve body in pressuretight relationship therewith; said sleeve to be internally threaded to receive the valve stem guide member 53 within which slidably operates a poppet type valve 54 biased by a spring 55 into seated relationship with respect to the passage 50. By means of a suitably aifixed adjustment knob 56, the member 53 may be rotated for movement axially within sleeve 52, so as to establish a desired spring bias against the valve 54.

It will be noted from Fig. 3 that with the piston in home position, the upstream passage 50 is blocked from communication with the chamber 30 by the respective piston elements 2| and 22. Initially, therefore, the fluid pressure is available at its maximum level to overcome the starting inertia of the operating elements. The cam drive of the shoe carriage effects maximum rotation of the carriage toward its operating position during the very early stages of piston lift, thereby requiring considerable force to be delivered to the links 33. Therefore, by the time the upstream passage 50 is sufficiently cleared by the piston head to become operatively effective, the shoe carriage will have completed the greater portion of its travel. By suitable adjustment of the valve bias, the operator may control the rate of movement of the buck and of the shoe during the latter portion of the shoe travel and during the greater portion of the buck travel to their respective operating positions. For example, by reducing the spring bias, a considerable portion of the oil discharging through the ports 41 may be by-passed above the piston head, thereby effectively slowing the piston drive. Conversely, by increasing the spring bias, one may appropriately reduce oil flow through the by-pass structure. In any event, it should be noted that if at any instance before the piston head assembly covers the downstream passage 5| any normal restraint against the movement of the shoe carriage or buck develops; for example, by the op- 6 erator in an emergency seeking to hold back the shoe while leaving the electric motor 18 energized, the hydraulic pressure within the chamber 30 will be expended by passing through the by-pass circuit and the ironer will not be exposed to damaging strains. Thus, the by-pass structure serves as a pressure relief means. After the piston has risen fully, at which time the shoe is in ironing position, the downstream port 5| is closed by the piston head and the balance of pressure on each side of the valve 54 becomes equal, making full pressure available against the piston head 22 for exertion of ironing pressure.

While I have shown a particular embodiment of my invention, it will be understood, of course, that: I do not wish to be limited thereto, since many modifications may be made; and I, therefore, contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A power unit for an ironing machine or the like, comprising a cylinder and a combined piston and hydraulic pressure generation means therein, including a hollow piston structure having extending flange means providing a piston head and piston ring securement means, a pump disposed within said flange means, said flange means defining a chamber for said pump with rectilinearly extending outflow passages, said passages having pump discharge ports extending through said piston head for discharging liquid forwardly of said piston head to propel the piston, means providing a reservoir of liquid within said cylinder to supply said pump, motor means within said cylinder to operate said pump, means defining normally open apertures through said flange means communicating directly between said reservoir and the space forwardly of said piston head to return liquid to said reservoir upon return movement of said piston means, valve members slidable within said outflow passages to close said return flow apertures and open said discharge ports during pump operation, and biasing means for said valve members to close said ports and open said return flow apertures upon cessation of pump operation.

2. A power unit for an ironing machine or the like, comprising a cylinder and a combined piston and hydraulic pressure generation means therein, said means including a hollow piston structure having piston ring means engaging with the cylinder wall, a pump disposed within said structure, motor means within said cylinder for driving said pump, means affording a reservoir of liquid to be drawn by said pump, an outlet passage from said pump, said passage having a discharge port for discharging oil forwardly of said piston to propel the piston, means defining a normally open aperture through said piston structure into said cylinder for returning the discharged oil directly to the reservoir on return movement of said piston, valve means disposed within said pump outlet passage and responsive to pump discharge pressure to close said return passage means during pump operation, and means biasing said valve to open said return passage means upon cessation of pump operation.

3. A power unit for an ironing machine or the like, comprising a cylinder having a combined piston and hydraulic pressure generation means therein, said means including a hollow piston structure having piston ring means engaging with the cylinder wall to divide said cylinder into a Pr sur ehe eber and a reser oi cham er, a pump d s osed within sai struet e. motor means w in said eylinti r for driving said pum means aff n e mmuaiea io oi i id from the reservoir chamber to said pump to be aw by a p p, a outle pas age i om said p mp, said passa e avi a di eharee port o discharging liquid intQ sa d eylin er pressure chamber to propel the piston, a normally open etur po t t g id. piston st uc ure 9 i id flo r c y ro said p es u e hamber to said reservoir chamber on return movement of said p on, valve mean is os d ithin sa d pump outlet passage and responsive to pump discharge r re to cl e said etu n pe durin pump op a i mea s fo b as ng said valve to pe aid r turn po upo ces ti of pum operation, and an adjustable pressure lay-pass system efiective during a portion of the piston power stroke to return some of the liquid ,di scharged into said pressure chamber to the reservoir chamber to limit the liquid pressure effeotive for mov the p sto 4 A power unit for an ironing machine or the like having a cooperating buck and shoe, comprising a cylinder and a combined piston and hydraulic pressure generation means therein, including a hOllQW piston structure having extending flange means providing a piston head and piston ring seeureinent means dividing said cylinder into a pressure chamber and a reservoir chamber, a pump disposed within said flange means, 'a ohamperjfor said pump defined by walls 8, Within said flange means and having reotilinearly extending outflow passages, said passages having outlet ports extending through said piston head for dischargin fluid into said pressure chamber formed by said piston head and an end portion 0? said eylinder to propel said piston, means providing communication from said reservoir cham? er of flu d o suppl a d pump m tor m ans ithi said in e to p ate sai pump, a by.- pass passa e from aid pressure chamber to said reservoir chamber, anadjustable pressure reguer t n s l t-pa s pas a e to lim t th pre o the oil era in sa pi t during a portion of thepower stroke, the portion of a d yp sa een said essu e regulator and said reservoir being positioned to be blocked by said piston prior to the oomplev tion of the power stroke.

a repre- References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,112,466 Maloon Mar. 29, 1933 2,170,702 Wardwell Aug. 22, 19:39 13 Ev n 2,475,304 Bariffi July 5 1949 2,599,308 Worst et a1 June 3, 1953 FOREIGN PATENTS Number Country Date 380,774 Great Britain Sept. 22, 1932 

